


Jump

by ShitL0rd



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Angst, Belly Rubs, Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Ectobiology, Fluff and Smut, Gentle Papyrus, Hurt/Comfort, Light Bondage, Light Masochism, Light Sadism, M/M, Sibling Incest, Suicidal Thoughts, Suicide Attempt, Waterfall (Undertale), sweet papyrus
Language: English
Status: Completed
Published: 2017-02-11
Updated: 2017-02-11
Packaged: 2018-09-23 11:09:55
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 3
Words: 4,330
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9653387
Author URL: https://archiveofourown.org/users/ShitL0rd/pseuds/ShitL0rd
Summary: UF Sans attempts suicide





	1. Chapter 1

**Author's Note:**

  * For [metaNightmare](https://archiveofourown.org/users/metaNightmare/gifts).



> Just a heads up, there will be no name-calling or abuse. Fell will be a good brother like he's supposed to be, and Red will not be used like an object.
> 
> If you want rape, go somewhere else.

Sans had only heard rumors. Rumors that there was a secret place in waterfall monsters went to fall down. Granted, he'd heard it one night at the bar a bit more than slightly inebriated, so for the longest while he never thought much about it. Now, it was the only thing on his mind.

He takes the long route, thinking over the events of his life. He goes a bit quicker, coming across one of his brother's terrifying puzzles, afraid of what would happen if he was cought all the way out here. When nobody comes, he is both relieved and further disappointed.

Waterfall is not as foreboding as it usually seems. Instead of fearing the rushing water and murmurs of the past concealing monsters on the prowl for free EXP, it seemed more like a farewell march to him. He passes a flower preserving the final screams of someone. He chuckles dryly to himself. He wouldn't get such an honor as to be remembered even by a flower.

Even by his own brother.

If he could feel more like an idiot when he finds the so-called secret spot, he would, because it's not very easy to miss. He crosses the wilting bridge flowers to a broken-down dock, where at least two dozen monsters' shoes were neatly lined up at the edge. In fact, there seemed to be a spot just for his. He sits on the bench, listening to the cries of a child apologizing to its parents, and contemplates leaving his brother some sort of goodbye. But that would take too much effort.

Besides, it's not like he would even care.

***

Fell was beyond pissed now. He went just about everywhere, looking for his brother. Ge checked Grillby's, all of the sentry stations, heck, he even checked to see if Red was hanging out with Alphys!

Just as Fell began to feel fury and admittedly some concern well up in his chest, he suddenly remembered a distant memory. He and Sans would occasionally visit Waterfall.

Fell smirked at his absolutely flawless and clever mind. He began to make his way to Waterfall...

***

Sans sighs as deeply and quietly as he can. He doesn't want to tarnish the kid's last pleas, they'd matter much more than anything his disgusting mind held. He bends down to untie his own shoes. He stares at the ratty sneakers on the floor for a few moments, picking them up. He slowly ties the laces back up so they at least would look a little nice for the next unlucky soul to fall down here.

He's just wasting time. The longer he's here, the longer he stains the underground with his presence. He slowly gets up, setting the shoes down between the rest. They look so much different than the others, older, worn out and frayed, the bottoms and edges of the laces stained black from years of stepping through dusty streets.

He stands just in front of them, his sockless feet only half on the dock. The splinters hurt, but he ignores it. Besides, it won't even matter in a few moments.

The water is disturbed by a drop of something. He's glad he can't see his pathetic reflection in the glowing water.

***

Papyrus hurriedly rushed through Waterfall. He checked the bench with a quiche onder it, he checked the small pool... Of course, Sans could be at the waterfall itself!

Fell began to follow the path, but with each step, the darker the atmosphere. He could hear the voices of monsters murmuring despairs into the echoing flowers. A chill ran down his spine as a certain flower echoed a very familiar chuckle. Sans' chuckle! He was close! Papyrus picked up his speed, feeling very anxious.

***

Sans breaks out into a cold sweat, hearing what was very clearly someone running in his direction. He looks down at the water. It was now or never. His body shakes, willing itself to take the last step, the final jump, to even goddamn lean forward enough to fall, to stop being such a pussy and get it over with! What was he so scared of?!

He squeezes his eyes shut, willing himself not to cry anymore. He can't breathe as he feels himself falling.

Papyrus was now dashing towards his brother in horror. "SANS, YOU STUPID BASTARD!!!" He suddenly used his blue magic and yanked the smaller monster back rather roughly. Fell finally caught up to the bridge and dragged Sans' body far back and into the grass.

Papyrus gripped Sans' shoulders tightly and his voice was hoarse. "WHAT THE FUCK WHERE YOU DOING!?" He felt a lump grow in his throat as he noticed Sans' small, beat-up feet. "AND WHERE ARE YOUR SHOES!?"

Sans slowly shrinks in on himself, hoping he'd just dust on the spot. He doesn't dare open his eyes and face his brother's wrath. He'd not only failed, but, once again, Papyrus had to save his sorry ass. He just holds his breath, suffocating any sobs that dared try and escape, his small frame convulsing with unheard cries. Stars, why is he so pathetic? 

Papyrus was at his wits end and felt like he could explode any moment. Why was Sans not talking? Most importantly, what would happen if Papyrus didn't catch him? "AREN'T YOU GOING TO FUCKING ANSWER ME, YOU WHELP?"

As soon as Sans opens his mouth, just like he'd expected, all that came out were gross sobs. He covers his face as much as he can, letting out several choked "I'm sorries" between his cries. God, why didn't he stop wasting time and just disappear? 

Papyrus' brows lifted in confusion and worry. The grip on Sans' shoulders relaxed and he then lowered his voice. "Sans...? Sorry for what? What where you even doing here?"

Sans' shaking lets up a little bit at the softer tone to Papyrus' voice. He couldn't be hearing right... he slowly lowers his hands, looking up at him with fuzzy, unfocused eyelights.

"I-I...."

He looks back to the dock. Surely his brother was just trying to get a rise out of him. Why would he care...?

"... I tried to j-jump...."

Papyrus could feel his soul crush under a heavy weight of... Guilt? He leaned in, tempted to scream, but held his composer for the sake of Sans. "Why?! You could've killed yourself!" 

Sans is shaking like a leaf. He looks down, ashamed of himself. Ashamed of his actions. Ashamed of his failure. His eyes wander back to all of the shoes, voice hardly a whisper.

"I-I know...."

Papyrus' eyes widened in horror. His grip tightened and he began to feel dizzy. "D... Don't tell me you were going to kill yourself??..." He wished the answer would have been a no. 

Sans squeezes his eyes shut again, not wanting any more tears to draw attention to how pathetic he was.

"Wh-what does it matter? N-nobody would have even noticed...."

He unconsciously tries to shrink away from the touch, but Papyrus' grip is just too strong. Maybe if it was a little stronger, he would just....

Papyrus bristled at the comment. "Are you fucking serious?!" He bared his fangs and forced Sans to look at him. "I would have noticed, bonehead!!!"

Papyrus sighed and rubbed his temples, trying to ease the anger. "It matters because you are my brother. You took care of me when I was young, so it's my duty to care for you. Sans..." he cut himself off, not used to being soft. 'But now is the time to be soft. This is your brother.'

Sans looks at him, eyes filled with translucent red tears.

"I-I'm sorry... I-I'm... I'm such a failure... a hindrance, a roadblock, dead fucking weight... wh-why... why do you still want me around...?"

Papyrus couldn't take it. He surged forward and kiss Sans roughly. "B-because I love you!" 

Sans stares at him, eyes wide in shock. The shaking lessens, and the tears slow some. He brings a trembling hand to his mouth.

"... Y-you... you do...?"

Papyrus huffed and blushed a deep red. "O-OF COURSE! If I didn't love you, I would've killed you a long time ago." 

Sans... isn't sure how comfortable he is with that statement. He takes it as best he can, knowing that's the closest to a genuine compliment he'd ever get but... the second part unsettles him somewhere deep in his soul and he hates it, hates the cursed thing.

"B-boss, I... th-thank you...."

Papyrus hugged Sans tightly in silence. His soul began to pound as thoughts swam in his skull.

"Hush."

Slowly, Sans wraps his arms around Papyrus, burying his face in the ragged scarf. He starts to cry again, emotions jumping all over— love, guilt, fear, happiness....

"... B-boss... do I... do I really m-mean so much to you...?"

Papyrus flushed and hugged back tightly. He felt so vulnerable... Sensitive. "I'd never lie to you..." 

Sans' shaking slowly subsides. He pulls back some, looking up at Papyrus with hazy eye lights and a faintly red face.

"I-I'd like to go back home...."


	2. Chapter 2

Papyrus places Sans back on the couch. He then locks the front door and heads towards the kitchen. Many thoughts still buzzed in his skull. 

Sans watches him head towards the kitchen. He wants to follow him, but is too nervous of moving from where he'd been placed. He ends up just leaning pack, picking splinters from his feet with his sharpened phalanges to try and occupy his mind.

After a while Papyrus walks in with a mug of hot chocolate. He handed it to Sans and then joined him on the couch. 

Sans stares at the warm mug, then back up at Papyrus, not questioning, but touched.

"Thank you, boss...."

Papyrus blushed and looked down at the floor. "Ah, y-yes. You're welcome..."

Stars, could he get anymore awkward?! Why was it that he became so shy when showing affection to Sans? They are currently in a safe environment, but he still struggles to figure out what he's feeling.

Sans can hardly believe what he's witnessing. The Great and Terrible Papyrus? Nervous? The only times those words should be in the same sentence would be if the words "is not" is between them. He takes a sip of the hot chocolate. It's far sweeter than mustard, and while it burns a little at first, he continues to drink it.

"This is really good!"

Papyrus leans back and beams at the praise. "Nyeh, of course!" He couldn't help the small smirk that crept up on his face. Papyrus felt proud that Sans was okay now, thanks to him. 

Sans gives a small chuckle of his own. He looks down at his half-empty mug.

"I, uh... really should thank you... for, y'know, saving my life and all...."

Papyrus blushes a deep red. He can't find words... What's so hard about this? Papyrus shifts awkwardly in his seat. "Eh... Yeah..." 

Sans places his hot chocolate on the floor, turning more towards Papyrus. The sight of him blushing was surely a sight to behold. He tentatively extends a hand, letting it gently lay on the side of Papyrus' face and cheekbone.

Papyrus tensed and turned his head slightly and stared at Sans with large eyes. His soul fluttered in his chest at the sweet gesture. He wanted more... So much more... But he must keep his composer! 

Sans' eyes, out of habit, look down. He takes a deep breath to help regain his courage.

"C-can I, um... is it okay if I k-kiss you...?"

Papyrus turned towards Sans and flushed deeper. "Yes!" Oh, he spoke too quickly. Papyrus cleared his throat and responded more cooly. "I mean, yes."

Stars, if that wasn't precious... Papyrus might be sharp around the edges, heh heh, but he was just a softie wasn't he? He closes his eyes, leans in and kisses him.

Papyrus leaned forward and tilted his head a bit, his sockets half-lidded. He slowly held onto Sans' arms and lightly hummed into the kiss. 

Sans simply enjoys the kiss for a bit, not necessarily wanting to rush right into things. He pulls back, keeping his hand on Papyrus' face. A bit of curiosity pops into his mind as he remembers a certain book.

"I don't suppose you'd mind going on a date with me...?"

Papyrus held Sans' small hand and kept himself from smiling like a dork. "Of c-course!" 

Sans looks down at the way Papyrus' hand envelops his own. He stands up, a bit shakily but without issue, walking up to Papyrus' room with him. He waits for him to enter first though.

Papyrus blushes and walks in first. He bashfully sat on his bed. His soul felt like it could burst out of his chest at any moment. 

Sans follows, taking a close look around the room— action figures he'd gotten for him as 'Santa' (more like Sans-ta, heh, he'd have to use that one day), a box of bone attacks, a torn flag with a skull on it Undyne found... well, two out of three make him smile.

"So, uh... what is it that couples do on a date...?"

Papyrus flushed. "Well, according to my book, couples do hideously sappy things. They cuddle, go out to see movies, have a nice dinner...," He shuddered. "-...Mate..." 

Sans makes a kind of humming noise in response. He moves a little closer, fidgeting with his own fingers

"W-would you like to do anything...?"

Papyrus reached for Sans' hands and looked to the side. "A-ah... Yes, actually.." 

Sans looks down at their hands. The way his hands were encompassed by Papyrus' was... perfect. He looks back up at him.

"What... what would that be...?"

Papyrus squeezed the little hands gently. "Whatever you want..." 

Sans blushes a bit more and looks down at their hands.

"W-well, um... I guess there's something I'd like to try...."

Papyrus felt his soul swell at a rather... lewd idea. He kept his mouth shut though. "And that would be?..." 

Sans climbs onto the bed with Papyrus.

"W-well, um... it's...."

Sans' face turns red, eyes darting around. Stars, where did his courage go? He squeezes Papyrus' hands.

Papyrus blushed and cautiously pulled Sans towards him. "O-oh... Uhm.." He shifted slightly and tried to keep himself grounded. "Are you sure?" 

"Y-yeah... yeah, I'm sure."

Sans finds the resolve to look back up at him.

"I-if that's alright with you I mean...."

Papyrus sighs and leans in to silently kiss Sans. He continues to hold his brother's hand while the other wraps around the small body. 

Sans can't help but worry he'd said something to make Papyrus sigh like that. Nevertheless, he accepts the kiss, arching into his brother's touch.

Papyrus brushes his tongue against Sans' teeth and snakes a hand underneath his worn tshirt. He began to graze his fingers along the chipped and scared bone. 

Sans lets out a gasp. He hesitates to meet his tongue with his own, but once he does he starts to become more confident. He shudders under his touch, bringing his free hand up to wrap loosely around Papyrus' neck. 

Papyrus groaned into Sans' returned touch and pinned him onto the bed. He pushed his tongue deeper into his brother's mouth and began to... Huh?

Papyrus pulled back and noticed that Sans had conjured a round belly. He felt his face flush. "Nyeh!"

Papyrus shook his hands in the air defensively. "No, no, no! It's okay..." He trails off and reaches to the flesh and gently squeezes it. Papyrus flushes a bright red. "It looks v-vey nice." 

Sans lets out a small squeak as his belly is squeezed. His hands immediately fly up to cover his mouth.

Papyrus chuckles and bends over and runs his tongue along Sans' stomach. He hums softly and massages his brother's scarred hip bones. "So perfect," he murmured.

Sans squirms some under Papyrus' ministrations. Feeling his damaged hip bones being touched so intimately, along with the praise... his breathing starts to pick up, letting out a small whine.

Papyrus blushed and closed his eyes. He caressed Sans' ribs and nuzzled into his warm belly. "Are you still sure about this?" 

Sans nods.

"Y-yes, I... I, um... I've always wanted to, um...."

Sans mumbles something.

Papyrus begins to grope Sans' crotch and chuckles. He breathes heavily into his ear hole and licks the side of his face. "Tell me if you want to stop"


	3. Chapter 3

Sans' breath hitches. He starts to pant.

"I-I... I've always wanted... t-to be tied down...."

Papyrus raises an eyebrow and smirks deviously. He slowly takes off his battered scarf. "That's kinky~" 

Sans' soul is pounding in anticipation. The tone of Papyrus' voice, it always sends hills down his spine, but paired with the hungry way he's looking down at him... stars have mercy....

Papyrus reaches over and binds Sans' wrists tightly with the scarf. He then unbuckles his tight pants sensually. "What else do you like?~" 

Sans instinctively shrinks in on himself some. He can't take his eyes off of the way Papyrus unbuckled his pants.

"I-I, um... w-well...."

His eyes wander down to his own scarred hips.

"... I-I have so many scars... I wouldn't mind... o-one or two markings from you...."

Papyrus tossed his belt in some vague direction, the lift Sans up by the hood of his jacket. He placed Sans between his legs and smirked. "Tch~ You'll have to help me with a little issue, then I'll gladly spoil you rotten." Papyrus pushed Sans' face against his tightening bulge. 

Sans shudders with desire. He nuzzles against the bulge in Papyrus' pants. He takes the zipper between his sharpened teeth, pulling it down a bit teasingly.

"Anything for you, boss."

Papyrus hums in pleasure and squirms as his cock springs free from its confinements. It had two gold piercings beneath the head, and pre began to gather at the tip. He shuddered in anticipation. 

Sans lets out a groan at the musky scent coming from it. He lets his breath ghost over it, eyeing those piercings with arousing curiosity. He slowly drags his tongue up from the base to the tip.

Papyrus' breath hitches in excitement and his dick twitches. He clenches onto the bedsheets and bucks his hips a few times. "Mmh, fuck..." 

Sans glances up at him coyly before he takes the sensitive head into his mouth, suckling and lavishing it with his tongue. He takes it in a bit more to play with the piercings.

Papyrus grunts and continues to squirm against Sans' teasing. He releases short, hasty breaths. "Nnyyg, Sans..." 

Sans looks up at him curiously, yet mischievously. His tongue flicks and prods at the slit in the head.

Papyrus' gasps as his pupils roll to the back of his skull. "O-oh fuck! Fuck..." Do it again, please. It felt so good. He couldn't get himself to ask... 

Sans chuckles, continuing to attack Papyrus' weak spot, the taste of his spicy precum being enough to egg him on, let alone accompanied by those wonderful sounds Papyrus made.

Papyrus wheezed and pushed Sans' head all the way to his pubis. He drool slightly and bucked his hips deeply in Sans' throat. "Uhhng!" 

Sans gags some, but his eyes roll up from the strange new feeling, especially with those piercings sliding along his tongue and throat... he lets out a choked moan, the vibrations traveling directly up Papyrus' magic.

Papyrus grunts and pets Sans' skull and releases down his throat. His toes curl and his legs tremble. "Ngh, fuck! Haah, s-swallow all of it" 

Sans obliges, swallowing it all down. He slowly pulls off with a lewd pop, a string of saliva still connecting the two magic appendages. He pants, looking up at Papyrus.

Papyrus blushes and quickly wiped the sweat off of his forehead. "N-nyeh..." He bashfully looked to the side and huffed. "Did I taste okay?" 

Sans holds back a snort. Papyrus is such an adorable dork. Adorkable, if you will.

"You did, in fact. I could get addicted to you like mustard~"

Papyrus flushed a deep red and smirked. "Che! Of course, I taste better!" 

Sans' fingers fidget a bit with a loose fiber on the scarf binding his wrists.

"Heh. Can't argue with that. Though, I think I might have earned a bit of a reward...?"

Papyrus pushes Sans down and begins to slip off his shorts. "Nyeheh, of course~" 

Sans reflexively draws his legs together, not expecting the sudden change of position this time. His shorts come off with some tugging, chubby red thighs filling them out to match his belly. He bashfully looks away, feeling his cunt throb in arousal just beneath his boxers.

Papyrus' eyes widen at Sans' quivering lips. He slowly reaches and spreads the folds apart with his fingers. 

Sans gasps, exhaling shakily, unsure of himself again under Papyrus' scrutiny. He starts to bring his legs back together self-consciously.

Papyrus kisses Sans tenderly on his forehead and pushes inside a finger. "No need to hide that beautiful body of yours.." 

Sans blushes madly at the praise, gasping sharply as a finger is inserted. His warm magic clenches around it a little.

"A-ah, boss...."

Papyrus shudders and pumps in a second finger. "You're doing so good, Sans~" 

Sans starts panting, spreading his legs open some as he gives into the feeling. The praise and kind words seems to be doing wonders for him as well.

Papyrus sofly grunts and pushes in a third . "you're taking so much~" 

Sans lets out a deep moan, a slight but pleasant burn forming as his brother stretches and pumps him. He rocks his hips slightly down, trying to get those long fingers in deeper.

Papyrus slowly pulls his fingers out and lines the head of his length against Sans' labia. "Mmngh. A-are you ready?~" 

Sans looks nervous, but nods his head anyway. He doesn't want his fears to keep holding him back like this. He's come too far to let them pull him back down.

"R-ready as I'll ever be...."

Papyrus holds his breath and slides his head in with slight ease. It was so wet, yet so tight... He stilled for a moment, allowing Sans to adjust. 

Sans tries to relax to let himself unclench, but it's more difficult than he'd expected. He relaxes slowly, shifting a bit with a whine. 

Papyrus massages Sans' thighs, trying to relieve as much discomfort as he could. He wanted to claim his brother, fuck him into the mattress, fill him... "Is it too m-much?" 

Sans immediately shakes his head.

"N-no... no, please... more...."

Papyrus nods and pushes himself halfway into Sans. The conjured pussy desperately fluttered around Papyrus's erection, causing pre to dribble out. "N-Nngh"

Sans' eyelights roll up, the feeling foreign but not unwelcome. The stretching burns more now, but it doesn't seem to phase him in a negative way.

Papyrus grunts and begins to nibble on Sans' neck while he fully hilts himself. His hips twitched as he was sucked in deeper. "Ungh..."

Sans lets out a cry. He tries to cling to Papyrus, but his bound wrists leave him helpless. He finds himself enjoying that helplessness though. He lets his head fall to the side, baring his neck to Papyrus.

Papyrus groans and forcefully spread Sans' legs as far as they could go. He slowly pulled out and nibbled harder on the cartilage in his brother's neck.

Sans whines at the loss, trying to rock his hips back. He shudders at the treatment on his neck.

"A-ah, boss, please...."

Papyrus releases a shuddering breath and pulls out, just leaving the tip inside. He then slipped back in. He suckled on Sans' neck, prepping it for a harsh bite.

Sans shivers as he lets out a groan.

"B-boss... boss, please... m-mark me...."

Papyrus bucks in with and harsh thrust and sunk his shark teeth into Sans' neck. Blood bubbled up, and then he quickly stopped the bleeding with a few swipes of his tongue.

Sans lets out a choked cry as the bone as well as his magic is punctured harshly. He ruts back against Papyrus desperately.

Papyrus begins to slam harshly inside of Sans, making squelching noises. He grunts and squeezes Sans' thick thighs while he rubs his belly.

Sans is a writhing mess. Stars, the sharp pain contrasting with the immense pleasure, not to mention the way those piercings rub inside of him... it's just too much in all the right ways.

Papyrus' thrusts suddenly become frantic as he begins to reach his limit. "Nng, oh stars!" He fumbles and rubs Sans' clit along with his thrusts.

Sans lets out a cry as the pace becomes brutal. The stimulus to his clit has him keening, his cunt clamping down as he comes.

Papyrus groans and thrusts a few more times before he reached a violent climax. His sharp fingers dug into Sans' thighs as he filled him to the brim. "Take it all, fucking slut~"

Sans lets out a deep moan, his magic being pierced, being stuffed to the brim... he gladly accepts it all, eyelights rolling to the back of his skull in bliss.

Papyrus sighs in pleasure and hugs Sans sofly. "You did a good job," he murmured as he kissed his brother's cheek.

Sans leans into his brother's touch, still reeling from his orgasm. He tries to say something, but the words come out mumbled and tripping over one another.

Papyrus chuckled and kissed Sans' mouth tenderly. "Hush. You can't even speak properly." Papyrus sighed as he pulled out, watching his release flowing out of his brother.

Sans returns the kiss, groaning at the feeling of their juices flowing out. He cracks his eyes open to look at Papyrus with heart-shaped eyelights.

Papyrus chuckled and rolls over next to Sans' side, feeling warmth bubble up inside of him. He's never felt so... Good. "I l-love you," Papyrus gruffly said, looking to the side.

Sans stares at him for a second. Then... he laughs a little.

"Oh boss... I love you too...."

Papyrus flicked Sans in the head playfully. "Good."


End file.
